NSW in July 2012: Warm conditions return to NSW

Close to average rainfall, heavy rain in the west

NSW recorded a statewide average rainfall of 41.3 mm during July, slightly above the historical average of 39.4 mm. Rainfall was above average in the north and west of the state, but average to below average along the coast, with parts of the north and south coasts recording less than half their July average. The Murray Darling Basin also recorded 42.3 mm, above the historical average of 39.7 mm.

Most of the rain in inland NSW fell as a low pressure trough crossed the state between the 10th and 12th, with a second trough producing rain in northern inland NSW on th 13th and 14th. In western NSW, Fowlers Gap recorded 40.6 mm on the 10th, with 29.6 mm at Broken Hill Airport, its equal wettest June day on record. In northern NSW, Narrabri (Mt Kaputar) recorded 63.2 mm on the 11th with a 4-day total of 143.2 mm to the 14th, its wettest winter event since June 2005.

Lord Howe Island recorded 242.6 mm of rain during the month, the wettest July since 283.4 mm was recorded at the old site in 1979. There were only four days without rain during the month, the fewest since 1995 (4 days), with the wettest day recording 47.2 mm on the 14th.

Warm days and close to average nights

NSW recorded a statewide average maximum temperature of 16.0 °C, 0.7 °C above the July average. Most of the state was warmer than average during the month, with particularly warm conditions in inland parts of southern NSW. The warm days were associated with a succession of high pressure systems that crossed the state during the month, bringing clear conditions to the state, and a lack of significant rain events.

The statewide average minimum temperature during July was 3.5 °C, average for July. Nights were warmer than average in eastern NSW, particularly in the northeast, while nights were cooler than average in western NSW where southerly winds brought cooler air into the state.

The influence of a low pressure trough and rain event between the 10th and 13th brought a spell of very warm nights to NSW, with large areas more than 4 °C above normal, particularly in the north of the state. Several sites recorded their warmest July night on record on the 13th, with four consecutive nights exceeding 7 °C at Glen Innes, 10 °C at Inverell and 14 °C at Lismore, in the top 5 July warm spells on record.

The average temperature in NSW was consequently 9.8 °C, 0.4 °C above average. This is the first warm month for NSW since November 2011, and the 14th consecutive warm July.

Notes

A Monthly Climate Summary is prepared to list the main features of the weather in New South Wales using the most timely and accurate information available on the date of publication; it will generally not be updated. Later information, including data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review, usually published in the fourth week of the month.

This statement has been prepared based on information available at
1 pm on Wednesday 1 August 2012.
Some checks have been made on the data, but it is possible that results will change
as new information becomes available.

Averages are long-term means based on observations from
all available years of record, which vary widely from site to site.
They are not shown for sites with less than 20 years of record, as they cannot then be calculated reliably.
The median
is sometimes more representative than the
mean
of long-term average rain.

The Rank indicates how rainfall this time compares with the climate record for the site,
based on the
decile ranking
(very low rainfall is in decile 1, low in decile 2 or 3,
average in decile 4 to 7, high in decile 8 or 9
and very high is in decile 10).
The Fraction of average shows how much rain has fallen this time as a
percentage of the long-term mean.